Operation Killer

Operation Killer (20 February-6 March 1951) was a UN military operation of the Korean War that occurred when US general Matthew Ridgway ordered the US X Corps and US XI Corps to eliminate all communist forces south of the "Arizona Line" (which stretched from Yangpyoeng to Hoengseong in northern South Korea, 12-15 miles beyond the front battle line). The initial advance was slow due to treacherous terrain and a lack of bridges over the Chuchon River, but the UN forces routed all communist counterattacks before the end of February. The American 2nd Division faced strong elements of the Chinese 17th and 18th Divisions and lesser elements of the III and IV North Korean corps during its advance to Phase Line Arizona, and the UN forces employed the use of heavy artillery bombardment to push back the Chinese, who resorted to costly human wave attacks. The operation concluded in March, and the operation was immediately followed by Operation Ripper.